Field of the Invention
The invention relates to a device for the removal of a liquid lubricant from a bearing assembly for a shaft rotating about an axis, the bearing assembly having a bearing supporting the shaft, being acted upon by the lubricant and having at least one sealing assembly adjacent the bearing, the sealing assembly having a seal surrounding the shaft and a collector chamber located between the seal and the bearing and surrounding the shaft, the lubricant entering the collecting chamber from the bearing along the shaft and being removed from the collector chamber through a drain conduit.
The invention relates in particular to a slide bearing assembly in a turbine system, particularly in a steam turbine system. Particular attention is paid to slide bearing assemblies that must be protected as completely as possible against the escape of lubricant. Slide bearing assemblies that are usable in turbine systems, along with methods and devices for removing liquid lubricants and in particular lubricating oil from such slide bearing assemblies, are disclosed in European Patent No. 0 222 991 B1 and Published European Application No. 0 306 634 A2, both corresponding to U.S. Pat. No. 4,741,630. Slide bearings for turbine machines, particularly steam turbines, are described at length in those references. The inclusion of such slide bearing assemblies in journal bearings, thrust bearings and combined journal/thrust bearings is likewise presented.
One essential component of a device of that generic type is a sealing assembly for removing lubricant that escapes from the actual bearing and is intended to be retained in a suitable lubricant circuit. That objective is the product of simple economic considerations as well as thoughts on how to avoid contaminants in the vicinity of the bearing assembly. However, particularly in a steam turbine system, there is an additional essential aspect, namely to prevent the incursion of lubricant into the steam circuit, which impairs the thermodynamic process taking place in it and which moreover can cause contamination and corrosion. Especially a bearing assembly that must be mounted in an area acted upon by steam must be protected in a practical way against the escape of lubricant. That is especially true under the severe operating strains to which bearings and turbine systems and the like are exposed: In power plants, the turbine rotors rotate at speeds of several thousand revolutions per minute (typically,
3000 rpm in Europe and 3600 rpm in America), making for substantial relative speeds between the surfaces of the shafts and bearings that slide on one another in bearing assemblies. That entails very stringent requirements for the impingement of lubricant on the bearing, which in turn means considerable leakage of lubricant from the bearings. The slide bearing assemblies presented in European Patent No. 0 222 991 B1 and Published European Application No. 0 306 634 A2, both corresponding to U.S. Pat. No. 4,741,630, are especially constructed to overcome those problems. Above all, a speedy removal of the quantities of lubricant that escape from the slide bearings is intended to be assured, and moreover a removal of oil from the seals associated with the slide bearings should also be attained to a certain extent.
In every bearing assembly known until now, the removal of lubricant from the collecting ring disposed next to the bearing is accomplished essentially only by means of a natural gradient, which is achieved by suitably laying the drain conduits for the lubricant.